Definition
A NEXRAD radar display option that overlays terrain features — such as elevation contours, mountains, rivers, and coastlines — beneath the weather data, allowing pilots to see precipitation in relation to the ground below.
Plain English
A map setting that shows the shape of the land under the weather, so you can see where storms sit relative to mountains, valleys, and rivers.
Context Anchor
Seen on weather radar displays, map legends, and aviation weather graphics where a topographic background helps identify where weather is in relation to terrain.
Derivation
From Greek 'topos' meaning 'place' and 'graphein' meaning 'to write or draw.' A topographic view literally means a 'drawing of the place' — showing the shape and features of the land itself rather than political boundaries.
Why Pilots Care
Provides essential awareness of terrain that affects flight planning, radar interpretation, and obstacle avoidance.
Grounding Statement
TOPO is the ground-picture behind the weather picture.
Intuition Check
TOPO does not mean a special kind of storm or radar return. It means topographic information: the land and terrain used as a reference on the display.
Example Sentence 1
He switched the NEXRAD display to TOPO mode to see whether the line of showers was building over the ridge or drifting into the valley.
Example Sentence 2
Before departure the pilot reviewed the sectional chart's topographic shading to identify rising ground along the route.